Odometer wheel with frangible spokes

Abstract

An odometer type device for recording mileage and changes therein in a vehicle or the like, including a plurality of mileage indicating wheels placed on a shaft for rotation, each wheel being in closely spaced relationship to one another. The wheels each have a hub portion, an outer rim portion and integral spokes connecting the hub and rim portions. The spokes have a thinned midportion sufficiently weak so as to separate and disconnect the hub and rim portions to defeat attempts to move one wheel axially away from an adjacent wheel by imposing a significant axially directed prying force on the rim.

What is claimed is as follows: 
     
       1. In a mileage recording odometer including a shaft having a plurality of cylindrical digit wheels closely space thereon in side by side relationship to one another, an improved digit wheel, comprising: the digit wheel having a central hub portion, an outer rim portion and frangible connecting spokes therebetween responsive by breaking to prying of the rim portion relative to the hub portion; the hub portion having a central aperture through which the shaft extends; the hub, rim and spoke portions being integrally mold formed; the cross sectional area of the spoke being greater adjacent the hub and rim portions and progressively decreasing toward a narrow midportion so that any significant axially directed prying force on the rim portion generates a sufficient bending stress on the narrow midportion resulting in breakage of the spoke portion resulting in visual misalignment of the rim portion relative to the hub. 
     
     
       2. In a mileage recording odometer including a shaft having a plurality of cylindrical digit wheels closely spaced thereon in side by side relationship to one another, an improved digit wheel, comprising: the digit wheel having a central hub portion, an outer rim portion and frangible connecting spokes therebetween responsive by breaking to prying of the rim portion relative to the hub portion; the hub portion having a central aperture through which the shaft extends; the hub, rim and spoke portions being integrally mold formed of elastomeric material; the cross sectional area of the spoke being greater adjacent the hub and rim portions and progressively decreasing toward a narrow midportion so that any significant axially directed prying force on the rim portion generates a sufficient bending stress on the arrow midportion resulting in breakage of the spoke portion resulting in visual misalignment of the rim portion relative to the hub, the reduction in cross sectional area reduced by progressively decreasing the spoke width from a relatively large dimension adjacent the hub and the rim to a small dimension at the midportion. 
     
     
       3. In a mileage recording odometer including a shaft having a plurality of cylindrical digit wheels closely spaced thereon in side by side relationship to one another, an improved digit wheel, comprising: the digit wheel having a central hub portion, an outer rim portion and frangible connecting spokes therebetween responsive by breaking to prying of the rim portion relative to the hub portion; the hub portion having a central aperture through which the shaft extends; the hub, rim and spoke portions being integrally mold formed of elastomeric material; the cross sectional area of the spoke being greater adjacent the hub and rim portions and progressively decreasing toward a narrow midportion so that any significant axially directed prying force on the rim portion generates a sufficient bending stress on the narrow midportion resulting in breakage of the spoke portion resulting in visual misalignment of the rim portion relative to the hub, the decrease in cross sectional area is reduced by progressively decreasing the spoke thickness measured in the circumferential direction from a relatively large dimension adjacent the hub and the rim to a small dimension at the midportion. 
     
     
       4. In the mileage recording odometer set forth in claim 3 in which the decrease in cross sectional area is also reduced by progressively decreasing the spoke width from a relatively large dimension adjacent the hub and the rim to a small dimension at the midportion.